We even developed a full-fledged WYSIWYG editor in the past! (we were using TinyMCE before that and it wasn’t good enough for us, and then later we moved to CK) 
Now we do develop a lof of plugins for CK and I’m sure you’re very happy about that since otherwise you wouldn’t be able to insert macros in WYSIWYG, or have auto suggestion for creating links in WYSIWYG, nor be able to type “[”, etc. All this to say that developing plugins is not new and it’s also necessary. I don’t see that stopping anytime soon (not until CK Source itself or the CK community develop exactly what we need which is unlikely since it’s specific to XWiki). Now our preference always go in the direction of the less custom development possible ofc!
Note that the “someone” you mention has been so far a mix of:
- XWiki SAS who has sponsored most of the WYSIWYG work
- Some XWiki SAS clients who sponsored some WYSIWYG work too
- Some French and European research projects who have also sponsored some WYSIWYG work
Back to realtime, it’s an important feature we wanted to have working and integrated in XS in 2020 but we failed to achieve it and focused on other topics instead. It’s something we still want for 2021 though and dropping support for it in the WYSIWYG (i.e. relying on CKSource one) would be a hard choice (nothing has been decided yet).
Thanks for your POV!